1. Field of the Invention
This invention relates to a method and apparatus of propelling a pellet or BB from a gun using a shock-sensitive explosive cap or primer. As conventional firearms come under political attacks, gun enthusiasts are being forced to look to other means of recreational shooting. More and more, these enthusiasts are turning to air actuated shooting rifles and handguns to hunt and to target practice.
2. Description of the Prior Art
One of the earliest known air guns was the Austrian 1780 model named “Windbiichse” which literally translates to “wind rifle” in German. This early design was developed by Bartholomeo Girandoni. The concept of an air gun has not changed to a large degree since this early design. An air gun generally operates by having compressed air rapidly released from an air tight chamber behind a projectile that then travels rapidly through a gun barrel. The means by which this compressed air is generated is the greatest distinguishing feature amongst the many different designs of air guns.
The reservoir gun, sometimes called “multi-pump” gun, has a pump to compress air into a reservoir. These pumps can be operated in a myriad of ways, but the most common is to have part of the gun stock serve as a pump lever. The lever is hinged at one end and the other end is allowed to swing away from the gun barrel. The compressed air is generated by forcing the lever into the closed position. The reservoir gun, or pump design, is still commonly used in the United States. The most common application of this technology is typically referred to as a “BB gun.” This type of gun has been made famous by U.S. manufacturers Daisy and Crossman.
The greatest limitation about the “multi-pump” pneumatic gun is that it requires multiple compressions to generate enough compressed air to effective launch a projectile. Because of the typical design of the pump, there is a very real concern of pinching fingers between the pump lever and the gun barrel. Further, the pumping action requires a certain level of coordination and strength that may be troublesome to some users. Additionally, because it is a multiple pump design, it is problematic to generate consistent compressed air pressure in the chamber, and thus problematic to generate consistent projectile speed and trajectory.
Another air gun design is the spring-piston gun. This design typically is a single shot design that requires the breaking of the gun barrel at a hinged point to load a single projectile. After the projectile is loaded into the barrel, the barrel is then swung shut. While closing the gun barrel, a spring is compressed behind the projectile. When the trigger is pulled, the spring is released, and the air between the projectile and the plunger attached to the spring is compressed at a high rate of speed. This compressed air then forces the projectile through the gun barrel at a high rate of speed.
The problem with the spring-piston gun is that the spring is very strong or powerful. For the trigger to be effective, the spring is held back by a sear that has a very small engagement area. There is a very real danger that fingers can be pinched or even crushed if the sear was to unexpectedly release the spring.
Another method of compressing gas is to use pressurized air held in separate canisters or tanks. Typically, these canisters are filled with either carbon dioxide or compressed air. The canister then serves as a reservoir when attached to the air gun. A portion of the gas is ejected each time a projectile is fired out of the air gun.
The problem with this compressed gas system is that the pressure steadily decreases with each shot. CO2 canisters are also temperature sensitive, in that lower temperatures cause reduced pressure, which reduces velocity. Compressed air tanks are less sensitive to temperature variations. This variance in pressure causes the flight path of each projectile to be different. The difference in flight effectively renders the canister style systems ineffective as hunting or target shooting tools. Additionally, the canisters are bulky and heavy, making the use of the air gun awkward when the canisters are attached. Further, there is an inherent danger when handling canisters of highly compressed gas.
It is very desirable to have an alternative to traditional firearms that can be used by firearm enthusiasts to recreationally target shoot and hunt that has a high degree of repeatable accuracy. Therefore, an easily assembled and accurate non-firearm rifle or hand gun utilizing a new method of propulsion is important.